Broth culture yield vs traditional approach in the work-up of endophthalmitis

PURPOSE: To elucidate whether the Bactec Peds Plus F broth traditionally used for culturing body fluids in pediatric departments can also be used for vitreous cultures in cases with clinically suspected endophthalmitis, and to compare yields between this method and the traditional method. DESIGN: Prospective, comparative clinical trial. METHODS: All consecutive cases with clinically suspected endophthalmitis treated in our institution between July 2003 and November 2005 were included in the study. All cases were cultured both in the Bactec Peds Plus F broth and using the traditional method. RESULTS: Thirteen cases were included in this study. The overall growth rate for the Bactec broth was 28.4% higher than the traditional method (69.2% and 53.9%, respectively, P = .48). In two cases, one of acute-onset postoperative endophthalmitis due to Streptococcus mitis and one of delayed-onset postoperative endophthalmitis attributable to Candida albicans, there was positive growth only in the Bactec broth. CONCLUSIONS: The Bactec Peds Plus F broth can be used successfully in the examination of clinically suspected endophthalmitis. The method appears to have several advantages over the traditional method: time-savings, as only one medium needs to be inoculated, transportation to the laboratory is simpler as there is no need for immediate incubation, and there is no need to maintain a supply of fresh agar media. This method is especially suitable for office settings and remote clinics, but also can be used in hospital settings, as an adjunct, to increase the growth yield.     

Broth cultures yield vs traditional approach in the workup of infectious keratitis

PURPOSE: To elucidate whether BACTEC Peds Plus F broth, usually used for culturing body fluids in paediatric departments, can be used for corneal cultures from cases with clinically suspected infectious keratitis, and to compare yields between this method and traditional methods (blood agar, chocolate agar, a fungal media, and swab transport media). METHODS: All cases with newly diagnosed, nonviral, clinically suspected infectious keratitis with no prior antibiotic therapy, were cultured both in the BACTEC Peds Plus F broth and the traditional method. McNemar's test was used for pairwise comparisons of the rates of positive growth between the two groups. RESULTS: In total, 30 eyes were included in this study. The growth rates for the traditional method and the BACTEC broth were similar (50.0 and 53.33%, respectively, P=1.0). The overall growth rate for the two methods combined was 73.33%, which is 45.29% higher than the reported yield in the literature (average of 50.47%). CONCLUSIONS: Our results show that BACTEC Peds Plus F broth can be used successfully in the work-up of clinically suspected infectious keratitis. The method has, apparently, several advantages over the 'Traditional method:' time-savings, as only one medium needs to be inoculated, transportation to the laboratory is simpler as there is no need for immediate incubation, and there is no need to keep and maintain a supply of fresh agar media. This method is especially suitable for office settings and remote clinics, but also can be used in hospital setting, as an adjunct, when available, to increase the growth yield.     

The results of pars plana vitrectomy and silicone oil tamponade for endophthalmitis after intravitreal injections

To report the role of early vitrectomy and silicone oil tamponade in acute endophthalmitis following intravitreal injection. Medical records of eight patients who presented with acute endophthalmitis after intravitreal injection of different drugs were retrospectively reviewed. Initial treatment consisted of vitreous tap with cultures and injection of intravitreal antibiotics, with the patients subsequently undergoing pars plana vitrectomy and silicone oil tamponade within 24 h following initial vitreous tap. The mean time to presentation was 1.7 days (1–3 days). The initial best-corrected visual acuity was hand motion to 0.05 before treatment and 0.05–0.8 (Snellen) after treatment. Vitreous cultures were obtained from all patients, of which four were culture positive. Endophthalmitis was controlled in all patients. There was no retinal detachment or phthisis bulbi during the follow-up period (1–4 years). Acute endophthalmitis following intravitreal injection occurs rapidly and requires urgent treatment. If intravitreal antibiotics fail to control inflammation, early pars plana vitrectomy and silicone oil tamponade would be an appropriate option.     

Minimizing the endophthalmitis rate following intravitreal injections using 0.25 % povidone–iodine irrigation and surgical mask

Background

To examine the efficacy of complying with an infection control manual for intravitreal injection of anti-vascular endothelial growth factor (VEGF) preparations in reducing the rate of endophthalmitis.

Methods

We retrospectively reviewed intravitreal anti-VEGF injections conducted by vitreoretinal specialists at the outpatient injection room of a single university hospital between July 2009 and July 2012. The injections were conducted following an infection control manual established by our department. Doctors and nurses wore surgical masks, and disinfected the patient’s eyelid skin with 10 % povidone–iodine and then the conjunctiva with 0.25 % povidone–iodine. After putting a drape on the patient’s face, a lid speculum was placed. The conjunctival surface was again washed with 5 ml of 0.25 % povidone–iodine. After waiting at least 30 seconds, intravitreal injection was performed through povidone–iodine. Following injection, the injection site was again washed with 5 ml of 0.25 % povidone–iodine. Patients were treated with topical levofloxacin 4 times a day for 3 days before and after the injection.

Results

A total of 15,144 injections comprising 548 injections of pegaptanib sodium, 846 injections of bevacizumab, and 13,750 injections of ranibizumab were performed. During this period, no case of suspected or proven infectious endophthalmitis occurred. The endophthalmitis rate was 0 per 15,144 injections, (95 % confidence interval, 0.0–0.0 %).

Conclusion

The results suggest that endophthalmitis can be reduced to a minimum by preventing normal flora of the conjunctiva and bacteria in the oral cavity from entering the vitreous. For this purpose, an infection control manual that requires nurses and doctors to wear surgical mask and drape the patient’s face, irrigate the conjunctiva with 0.25 % povidone–iodine and wait at least 30 seconds before performing intravitreal injection is useful.     

Acute endophthalmitis caused by<Emphasis Type="Italic"> Staphylococcus lugdunesis</Emphasis> after intravitreal bevacizumab (Avastin) injection

Purpose To report a case of culture-positive endophthalmitis after intravitreal injection of bevacizumab (Avastin) resulting in a devastating visual outcome. Method A retrospective case report of a 51-year-old diabetic women who presented with further decrease in her vision, redness, and mild pain in her eye 3 days after intravitreal injection of Avastin for macular edema due to a branch retinal vein occlusion. Results Clinical diagnosis of endophthalmitis was made and, after obtaining a vitreous tap, intravitreal antibiotics were administered. Because of worsening of the endophthalmitis, pars plana vitrectomy was undertaken followed by repeat intravitreal antibiotics injection. The patient’s ocular condition improved dramatically; however, her visual acuity did not improve. The cultures from vitreous taps revealed Staphylococcus lugdunesis. Conclusion Intravitreal injection of Avastin may be associated with a risk of S. lugdunesis-caused endophthalmitis which can have a devastating effect on the final visual outcome.     

Associated factors and treatment outcome of presumed noninfectious endophthalmitis occurring after intravitreal triamcinolone acetonide injection

Background

To investigate the associated factors and treatment outcomes in patients with presumed noninfectious endophthalmitis after intravitreal triamcinolone acetonide (IVTA) injection.

Methods

Among 219 consecutive cases of 186 patients who had undergone IVTA injection for macular diseases, presumed noninfectious endophthalmitis was diagnosed if the patient showed severe inflammation in the anterior chamber and vitreous cavity within 7 days after injection but no organism was isolated on microbiological examination. Clinical features and previously performed surgical procedures were evaluated to assess their association with presumed noninfectious endophthalmitis using logistic regression. After surgical or medical treatment for endophthalmitis, the visual outcome was evaluated in all patients.

Results

Noninfectious endophthalmitis developed in six of 219 eyes (2.7 %). Previous vitrectomy, history of IVTA injection, and pseudophakia were significantly associated with the occurrence of presumed noninfectious endophthalmitis after IVTA injection (p?=?0.049, 0.034, and 0.009, respectively). Internal limiting membrane (ILM) peeling during vitrectomy also showed statistically significant association (odds ratio?=?13.6, p?=?0.017). Five of six patients (83.3 %) regained pre-injection vision.

Conclusion

In addition to previous vitrectomy, history of IVTA injection, internal limiting membrane (ILM) peeling, and pseudophakia may render the eye vulnerable to presumed noninfectious endophthalmitis following IVTA injection. Visual outcome shows generally good prognosis after treatment.     

Diffuse infiltrating retinoblastoma coexisting with ocular toxoplasmosis

A 4-year-old boy presented with unilateral endophthalmitis and echography revealed an abscess in the vitreous cavity. A pars plana vitrectomy with intravitreal antibiotic injections was performed with a presumed diagnosis of endophthalmitis; however, the patient returned after 10 days with fibrin reaction in the anterior chamber, iris nodules and cataract. The vitreous sample from the vitrectomy showed Toxoplasma gondii parasite, so he was treated with intravitreal clindamycin and lensectomy. The postoperative fundus examination revealed multifocal white patches with calcified deposits and cytology proved the diagnosis of retinoblastoma. Enucleation was performed in addition to systemic chemotherapy. To our knowledge, this is the first reported case of the coexistence of retinoblastoma and ocular toxoplasmosis.     

Evaluation of <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> staphylolysin (LasA protease) in the treatment of methicillin-resistant <Emphasis Type="Italic">Staphylococcus aureus</Emphasis> endophthalmitis in a rat model

Background  Therapy of S. aureus ocular infections is increasingly challenging due to emerging resistant strains. Staphylolysin (also called LasA protease) is a staphylolytic endopeptidase secreted by Pseudomonas aeruginosa. The purpose of this study was to evaluate the efficacy of staphylolysin as a therapy for experimental methicillin-resistant Staphylococcus aureus (MRSA) endophthalmitis, focusing on its bactericidal activity. Methods  Endophthalmitis was induced in the right eyes of 46 rats by an intravitreal injection of 50–160 MRSA cells. Two therapeutic regimens were evaluated: (i) an intravitreal injection of staphylolysin at 6 hours post-infection; (ii) two successive intravitreal injections of staphylolysin given at 6 and 30 hours post-infection. Control eyes were injected with vehicle alone at the same times. The rats were sacrificed 48 hours after infection, and the vitreous was withdrawn for determination of colony forming units (CFU). Potential adverse effects of intravitreal staphylolysin injection were assessed histopathologically in four uninfected eyes, enucleated from rats sacrificed 1 month after intravitreal staphylolysin injection. Results  In eyes treated by the single-injection regimen, staphylolysin reduced the mean CFU value per vitreous threefold as compared to control (2,055 ± 3,144 and 6,432 ± 6,389 CFU/vitreous, respectively; P = 0.02). The repeated injection protocol was more effective, reducing the mean CFU value per vitreous by two orders of magnitude as compared to control (1,148 ± 3,096 and 143,519 ± 151,358 CFU/vitreous, respectively; P = 0.0005). Histopathological analysis showed no structural damage in eyes injected intravitreally with staphylolysin. Conclusions  Staphylolysin is effective in the treatment of experimental MRSA-induced endophthalmitis in rats, and causes no morphological adverse effects to ocular tissues. Staphylolysin may be beneficial in the treatment of S. aureus endophthalmitis in humans. The authors have no proprietary interest in any aspect of this study. The authors have full control of all primary data, and they agree to allow Graefe's Archive for Clinical and Experimental Ophthalmology to review their data upon request.     

Endophthalmitis in the western Sydney region: a case-control study

Background : A retrospective case‐control study was conducted to investigate risk factors for endophthalmitis following routine intraocular surgery. Methods : A review was performed of consecutive cases of endophthalmitis from three teaching hospitals in the western Sydney region and matched controls from the same institutions between 1996 and 1998. Results : There were 31 cases and 66 controls. Eighty procedures were phacoemulsification, 15 conventional extracapsular cataract extraction, and two were penetrating keratoplasties. Of the 80 patients who had phacoemulsification surgery, 50 had a clear corneal incision, and 26 had a scleral incision (four were unknown). Logistic regression showed an increased risk of endophthalmitis with surgical complications (P = 0.002) and clear cornea temporal incisions (P = 0.007). Risk of endophthalmitis was reduced with use of subconjunctival injections (P = 0.008). The yield for the Gram stain was 47% and for culture was 67%. Anterior chamber tap in addition to vitreous biopsy alone did not increase the yield for microorganism (P = 0.78). Mean visual acuity on presentation was hand movement with 13 patients (50%) showing visual improvement following intravitreal injections of antibiotics (P = 0.003). Visual prognosis did not correlate with presenting visual acuity but appeared to be better in those who grew Staphylococcus epidermidis or were culture negative. Conclusions : Although this study is unable to draw definite conclusions regarding risk of endophthalmitis in clear corneal temporal cataract surgery, sufficient data suggest the importance of incision type and location. Surgical complication is an important risk factor for endophthalmitis. Use of subconjunctival antibiotic injections at the conclusion of the procedure is recommended.     

下方玻璃体腔注射后眼内炎高发病率研究

目的：探讨下方玻璃体腔注射比上方注射出现注射后眼内炎的几率是否更高。下方小梁切除术滤过泡眼内炎的发病率高于上方小梁切除术滤过泡,有可能是因为细菌聚集在下方的泪湖。

方法：经过广泛实践过的眼内炎病例数据库验证,发现在2a的研究期间内,有5例眼内炎病例。同时,为了评估注射部位对发病率的影响,对治疗过的909例1 121眼共计8672次注射进行了回顾性调查。

结果：5眼出现感染性眼内炎,80%的眼内炎病例均是下方注射,尽管所选病例中84.6%是位于上方注射。与感染有关的下方注射部位的危险比是(OR)22.1(P=0.006)。

结论：玻璃体腔注射后感染眼内炎的几率很小,仅为0.025%。避免在偏下象限进行玻璃体腔注射可能会进一步减小眼内炎的发病率。     

Pseudo-endophthalmitis after intravitreal injection of triamcinolone

AIMS: To describe an unusual endophthalmitis-like reaction after an intravitreal injection of triamcinolone acetonide in four patients. METHODS: Retrospective case series. RESULTS: Four patients are reported with an endophthalmitis-like reaction following an intravitreal injection of triamcinolone acetonide. There was a dense vitreous haze with severe reduction of fundus view in all cases. One case was treated as an infectious endophthalmitis but the vitreous tap showed no evidence of an endophthalmitis and no bacterial or fungal growth in culture. In all four cases, the vitreous haze cleared without specific treatment. The anterior chamber remained quiet in all cases but one, which was examined 30 minutes after the injection, and there was no periorbital inflammation or pain. CONCLUSION: Pseudo-endophthalmitis after an intravitreal injection of triamcinolone acetonide seems to be a distinct clinical entity that may resolve without specific treatment.     

Streptococcus Dysgalactiae Subspecies Equisimilis Endogenous Endophthalmitis Associated with Aortic Valve Abscess

Purpose: To describe a case of endogenous endophthalmitis from Streptococcus dysgalactiae subspecies equisimilis in the setting of an aortic valve abscess

Methods: Retrospective case report.

Results: A 72-year-old white male presented with fevers, encephalopathy, and decreased vision in his left eye. His visual acuity was 20/20 in his right eye and finger counting in the left eye. Workup revealed an aortic valve abscess. Examination of his left eye revealed dense anterior chamber fibrin and no view of the retina. B-scan ultrasonography revealed loculated hyperechoic areas consistent with vitreous inflammation. A vitreous tap and injections with vancomycin and ceftazidime were performed. Visual acuity worsened to no-light perception 5 days later. Vitreous and blood cultures grew Streptococcus dysgalactiae subspecies equisimilis. He received another intravitreal injection of vancomycin with no improvement.

Conclusions: Streptococcus dysgalactiae subspecies equisimilis is an emerging pathogen and may cause severe intraocular infections with a poor visual outcome.     

Endogenous Fungal Endophthalmitis Associated with Genitourinary Procedures

Purpose: To summarize the characteristics of endogenous fungal endophthalmitis (EFE) after genitourinary procedures.

Methods: Medical records of patients diagnosed with EFE after genitourinary procedures from a single center during a 6-year period were reviewed.

Results: Nineteen eyes of 15 patients were included. The interval time between procedure to symptom was 3.6 ± 3.6 weeks. As the initial treatment, 9/19 eyes underwent primary vitrectomy and 10/19 eyes underwent intravitreal antifungal injection . Candida albicans was the pathogen in 15 of 19 eyes. Systemic treatment with itraconazole was used in all patients. LogMAR best corrected visual acuity improved from 2.2 ± 0.9 to 0.9 ± 1.2 after treatment (p = 0.002) in 15 eyes that were followed-up for an average of 4.9 ± 2.1 years.

Conclusion: Genitourinary procedure is a predisposing factor for EFE. Candida albicans is the predominant pathogen. Normative systemic and local antifungal treatments improved the final visual outcome.     

蜡样芽孢杆菌性眼内炎的临床治疗观察

目的:分析外伤性蜡样芽孢杆菌性眼内炎的临床特征及抗生素敏感性,探讨早期诊治措施。方法:收集2019-01/2021-12陕西省眼科医院眼外伤中心收治的蜡样芽孢杆菌性眼内炎患者15例15眼的临床资料。记录受伤时间、受伤情况、术前视力、末次随访矫正视力、手术方式、细菌培养及药敏试验检测结果。结果:纳入患者15例15眼中,5眼单纯角膜穿通伤行伤口清创缝合联合眼内抗生素注射;10眼眼球穿通伤合并外伤性白内障及眼内异物行清创、白内障切除、眼内异物取出、玻璃体切除联合硅油填充及眼内抗生素注射。末次随访时,11眼(73%)治疗有效,眼球保留;4眼(27%)治疗无效,行眼内容物剜除。眼球保留的11眼中,视力下降1眼(9%),视力不变1眼(9%),视力提高1级4眼(36%),视力提高2级5眼(45%),治疗后视力较治疗前明显改善。相关性分析显示,病程与最终矫正视力呈负相关(r_s=-0.762,P=0.001)。纳入患者玻璃体液及房水样本培养均为蜡样芽孢杆菌生长,药敏试验检测均对万古霉素敏感。结论:万古霉素是治疗蜡样芽胞杆菌性眼内炎的有效药物,尽早进行玻璃体切除联合硅油填充、万古霉素...     

Endogenous Candida endophthalmitis after induced abortion

Purpose: To report two young healthy women who developed endogenous Candida endophthalmitis after undergoing surgically induced abortion.Method: Case reports.Results: In two eyes of two patients, a diagnosis of Candida endophthalmitis was established by typical fundus appearance, positive vaginal culture, and, in one case, positive vitreous culture. After vitrectomy and intravitreal amphotericin B injection, one eye of one patient had a best-corrected visual acuity of 20/200, whereas one eye of one patient, who had systemic corticosteroid treatment before the correct diagnosis, developed recurrent retinal detachment and a best-corrected visual acuity of counting fingers.Conclusions: Induced abortion may cause endogenous Candida endophthalmitis in young healthy pregnant women. Systemic corticosteroid treatment may increase the risk of endophthalmitis.     

Effect of intravitreal dexamethasone on vitreous vancomycin concentrations in patients with suspected postoperative bacterial endophthalmitis

Purpose To study intravitreal dexamethasone and vancomycin concentrations, when used together in patients with suspected postoperative bacterial endophthalmitis. Animal studies had suggested that dexamethasone might decrease the concentration of vancomycin. Design Prospective randomized clinical trial in a tertiary referral center. Methods Twenty-nine consecutive patients with suspected postoperative bacterial endophthalmitis underwent a vitreous biopsy followed by intravitreal injection of antibiotics (0.2 mg vancomycin, 0.05 mg gentamicin) and 400 μg dexamethasone or placebo. After 3–4 days, the intravitreal injection of antibiotics and dexamethasone or placebo was repeated. In 18 patients, a second biopsy was taken for repeat culture and measurement of vancomycin and dexamethasone concentrations. Results In 20/29 patients (69%) the first vitreous cultures were positive; the second culture was negative in all cases. Thirteen out of 29 patients received dexamethasone. Dexamethasone concentrations showed an average of 25 ng/ml 3 days after injection, with an estimated half-life of 5.5 h. Vancomycin concentrations in patients given dexamethasone tended to be higher compared with those in the placebo group (P=0.061). Conclusion Intravitreal dexamethasone does not lead to decreased vancomycin concentrations, when given simultaneously in the treatment of patients with suspected bacterial endophthalmitis.     

Clinical profile and outcome in Bacillus endophthalmitis

OBJECTIVE: To study the clinical presentation, microscopic and organismal culture correlation of vitreous, and species-specific outcome in Bacillus endophthalmitis DESIGN: Retrospective noncomparative case series. INTERVENTION: Thirty-one culture proven Bacillus endophthalmitis patients between January 1991 and February 1998 underwent vitrectomy and intravitreal antibiotic injection. Lensectomy was combined when considered essential, and on a few occasions intravitreal dexamethasone was added. The patients also received topical and systemic antibiotics. The undiluted vitreous biopsy was the source for microbiologic evaluation (microscopy and culture sensitivity). MAIN OUTCOME MEASURES: The duration of symptoms, the presenting visual acuity, and influence of intravitreal dexamethasone with intravitreal antibiotics were examined for any statistical correlation with the final visual acuity. RESULTS: Trauma was the major cause of infection. Vitreous biopsy microscopy demonstrated gram-positive bacillus in 28 of 31 cases, and polymicrobial infection was seen in 12 instances. All Bacillus species were sensitive to gentamicin, followed by vancomycin and ciprofloxacin. Clinical treatment within 7 days of symptoms, use of intravitreal vancomycin, and absence of polymicrobial infection were associated with better visual outcome. CONCLUSIONS: With appropriate treatment that essentially consists of vitrectomy and intravitreal antibiotics, patients with Bacillus endophthalmitis are likely to benefit in many instances. Gram-positive bacilli detected on vitreous microscopy should be empirically treated as Bacillus species unless otherwise proved.     

Infectious and noninfectious endophthalmitis after intravitreal bevacizumab.

AIMS: The aim of this study was to evaluate the rate of infectious and noninfectious endophthalmitis after an intravitreal injection of bevacizumab. METHODS: This clinical interventional case-series study included 1218 intravitreal injections of 1.5 mg of bevacizumab consecutively performed for 684 eyes with exudative age-related macular degeneration. Among the injections were 534 reinjections. Follow-up after each injection was at least 4 weeks. RESULTS: One (1) eye developed an infectious endophthalmitis 3 days after a second injection. In none of the other eyes, were signs of an infectious or noninfectious endophthalmitis observed with the cellular infiltration or amorphous opacification of the vitreous as marked by the Tyndall phenomenon in the anterior chamber, retinal infiltration, or pain. CONCLUSIONS: The rate of infectious endophthalmitis after an intravitreal injection of 1.5 mg bevacizumab may be approximately 1:1000, similar to injections of other drugs available thus far.     

Managing bevacizumab-induced intraocular inflammation

The outcome of four cases of sterile endophthalmitis that developed after intravitreal injections of bevacizumab has been reported here. All four eyes received 1.25 mg/0.05 ml intravitreal bevacizumab from 0.2-ml aliquots for different etiologies. The inflammation predominantly involved the anterior chamber with mild vitreous reaction. All patients were culture negative and regained preinjection visual acuity and were culture negative following intravitreal antibiotic administration. This report highlights that intravitreal bevacizumab can cause sterile endophthalmitis and this has to be kept in mind, and clinical judgment should be used to differentiate it from infective endophthalmitis.     

Intravitreal vancomycin and gentamicin concentrations in patients with postoperative endophthalmitis

BACKGROUND/AIMS: To study the intravitreal antibiotic concentrations and the efficacy of an intravitreal dosing regimen to treat patients with postoperative bacterial endophthalmitis. This regimen, based on pharmacokinetic/pharmacodynamic considerations, relies on a repeat antibiotic injection of a lower dose than is generally used. METHODS: In consecutive patients with suspected postoperative endophthalmitis a vitreous biopsy for bacterial culture was taken before 0.2 mg vancomycin and 0.05 mg gentamicin were injected intravitreally. After 3 or 4 days a second biopsy was taken for bacteriological culture and to measure intravitreal vancomycin and gentamicin concentrations, followed by a repeat injection of 0.2 mg vancomycin. RESULTS: 17 patients entered the study. In 11 patients the initial bacterial culture was positive, predominantly coagulase negative staphylococci. All second vitreous biopsies were sterile. Intravitreal vancomycin levels varied between 2.6 and 18.0 microg/ml (mean 10.3 (SD 4.1) microg/ml) after 3 days and between 3.1 and 16.6 microg/ml (mean 7.5 (6.2) microg/ml) after 4 days which is well above the minimal inhibitory concentration for most micro-organisms. Concentrations of intravitreal gentamicin varied between 0.90 and 3.3 microg/ml (mean 1.6 (0.72) microg/ml) after 3 days and between 1.2 and 2.6 microg/ml (mean 1.9 (0.99) microg/ml) after 4 days. CONCLUSION: This dosing regimen resulted both in adequate intravitreal vancomycin and gentamicin levels for over a week as well as in negative second cultures. This study also provides new information on intravitreal vancomycin and gentamicin concentration over time in patients with postoperative endophthalmitis.